Many user applications require a minimum amount of resources, e.g., communications bandwidth, to be useful. One example is traditional voice telephony that below either a target minimum bandwidth or above a maximum delay becomes unusable. During call set-up in traditional fixed telecom networks, a signaling channel first checks that sufficient resources exist between the caller and callee before admitting the call and ringing the callee in the case of voice. If there is insufficient resource then the call is refused with a network busy signal. Once admitted, calls are usually dropped by the network only if equipment fails or due to pre-emption mechanisms such as emergency over-rides. This model has continued into much of the traditional wireless industry where the resources are checked and then only dropped under network control as before. A new source of network failures though in wireless networks is that the hand-off between cells can result in a dynamic step-change in network conditions (new cell being fully occupied) that can cause the call to be dropped.
In existing cellular systems the media flow (e.g. voice and/or audio) and call control channel are tightly coupled resulting in both the call signaling and call media forcibly being dropped at the same time. This prevents the signaling channel from being used to advise the mobile node of the resource problem and give the MN options as to how things should proceed. In next generation IP data applications, the session control signaling, e.g., session signaling which may be implemented using, e.g., Session Initiation Protocol—“SIP” and media planes used to implement data transfer and data application signal using, e.g., Realtime Transfer Protocol—“RTP”, are designed to be distinct and separable. This allows, in some IP based communications systems, session control signaling and data signaling to be controlled independently.
In IP based applications, multiple user of an IP device may interact as a group, e.g., as part of a group game session. Dropping group members due to the temporary loss of bandwidth by an individual member can result in an inconvenient and un-enjoyable experience for the remaining group members. The sudden loss of a player may leave the other players without notice as to the dropped player's absence. Furthermore, the need for a dropped player to establish a new communications session in order to rejoin the group can result in relatively lengthy delays even after bandwidth has been restored to the dropped member. It would be far more desirable if a group member, e.g., player, subject to a sudden decrease in bandwidth could notify the other group members of a temporary absence and simply halt data communications without terminating the control portion of the group communications session. Thus, the other group members would be aware of the temporary absence of the group member subject to temporary bandwidth limitations and the group member can reestablish the data portion of the connection as soon as bandwidth is restored without having to establish an entirely new communications session.
In some cases, sudden decreases in bandwidth may be due to re-allocation of bandwidth in a cell in which a mobile node is operating or the previous allocation of bandwidth to other mobile communications users in a cell into which a mobile node is traveling. When confronted which such bandwidth problems, which would normally result in a connection being dropped, it would be nice to give the user who is about to have a connection dropped the opportunity to upgrade the user's priority, e.g., by paying a premium, to maintain an existing communications session. In this manner, a user could prevent the loss of the connection by selecting, e.g., to pay a premium to have the connection maintained. Unfortunatley, existing communications systems do not offer a mobile node user this opportunity.
In view of the above discussion, it is apparent that there is a need for methods and apparatus that would allow a communication session to be maintained even when changes in conditions, e.g., due to a mobile device's poor location or signal interference, result in insufficient resources to continue the data portion of the communications session. In addition, there is a need for providing users of mobile devices an opportunity upgrade their relative priority in terms of resource allocation before dropping a connection due to a resource request from a mobile device having a higher priority or because of the previous allocation of the required resources to another device.